17 Jul Clay
I’ve been experimenting again. In fact I think I’m always experimenting a bit. I always want to try out things and ideas that are new to me, so I rarely spend a day in the workshop without trying out a variation on a shape, a new glaze recipe, or a new clay body.
Recently I’ve been looking at mixing clay bodies to try to get the best performance and colour from the clay.
Because I push the terracotta that I use way beyond its guide temperature, I sometimes have problems with it. I relish the random bloating that often appears on the surface as it adds character and texture. But it really struggles when I start trying to add some glazing. I want to go beyond the bare clay body and explore using glazes over the dark background that the reduction firing gives me. Some tests I’ve done so far have had some lovely results but also some extreme and very disappointing failures.
This large pot is one of two that came out with cracks through the body of the piece . I did plenty of tests of this glaze on smaller pieces, which came out fine. But when scaling up to larger pieces, it just didn’t cope. I like the look achieved on this pot and it now sits in my lounge looking like there’s nothing wrong, but I know it’s fatally flawed.
You can buy black stoneware, but where would be the fun in that? But seriously I much prefer the subtle tones you get from the reduction fired terracotta I use. So I’ve been mixing the red clay with other clays to make a more robust body whilst retaining the iron content. I’ve also tried a few tests with an ‘agate-ware’ look by leaving the clays only roughly mixed to get a sort of marbling effect (hopefully).
I’ve also been testing red clay slip over a stoneware body as well as using pure red iron oxide over a stoneware body. When I do a glaze firing in a couple of weeks, it will be interesting to see how my glaze will come out on these tests, and see if they all survive!
I’m sure what I’m trying here is nothing new and there may be others out there who can tell me about their trials in this area. But there’s nothing like learning by doing, even if sometimes the lessons are painful ones.